1. Field of the Invention
The present invention relates to an apparatus and method for preventing a writing error occurring on an optical disc, and more particularly, to an apparatus and method for preventing a failure in writing data to an optical disc at a high speed.
2. Description of the Related Art
With the appearance of the digital age, compact discs (CDs), digital versatile discs (DVDs), and the like have been used as information recording and/or reproducing media.
In order to optimally and rapidly process and/or represent various types of data, competitive attempts to increase speeds of writing data to and reading data from an optical disc have been made.
However, the increase in the writing and reading speeds causes errors to occur when writing and reading data. As the writing and reading speeds increase, errors may occur. In particular, the probability of the occurrence of errors during writing is much higher than the probability of the occurrence of errors during reading.
Among those errors, a write failure takes place due to several factors, such as radial noise of an optical disc, etc. For example, when a 24× optical disc and a 48× optical disc have the same identification (ID), an optical disc drive recognizes the 24× and 48× optical discs as optical discs of the same speed. Thus, although writing is successfully achieved on the 24× (or 48×) optical disc using a 48× (or 24×) optical disc drive, writing quality may be poor. That is, since an optical disc drive recognizes optical discs having different writing characteristics as the same type of optical disc due to the same ID and then performs writing on them, errors may occur.
In a case where problems arise during packaging of discs, writing errors may occur due to focus drop and/or untracking, variations in the characteristics of an optical pickup and external factors.
There are several conventional techniques for preventing writing failures.
A first conventional technique is disclosed in Japanese Patent Publication No. 2000-163751. In the first conventional technique, information on an Absolute Time In Pre-groove (ATIP) signal is read from an optical disc to determine a writing speed of the optical disc. Next, writing is performed in a test area of the optical disc at optimal power control (OPC) corresponding to the determined writing speed and an optimal writing speed is extracted from the writing characteristics of the test area to write data in a program area. Thus, in the first conventional technique, since writing is performed in the test area and then in the program area, writing quality can be secured. However, the writing time increases due to writing delays.
A second conventional technique is described in Japanese Patent Publication No. 2001-266474 in which a number of rotations of an optical disc is controlled based on an ATIP signal detected from a wobble signal. A counterclockwise rotation of the optical disc shifts to the clockwise rotation using the ATIP signal. Next, a clockwise rotation controller calculates a difference between the counterclockwise rotation and the clockwise rotation, and a bit operation is performed on a target coefficient. The difference value is compared with the bit operation result. Thereafter, the ratio of the difference value to the target coefficient is determined to generate a signal to indicate the time when the counterclockwise rotation shifts to the clockwise rotation. Also, a shift control signal is applied to a rotation control shifter to shift the counterclockwise rotation to the clockwise rotation. As a result, a writing error may be prevented. However, the second conventional technique has the following disadvantages. The conditions such as the target coefficient must be preset to prevent the writing error and when the ATIP signal has an error, writing errors may not be prevented.
Japanese Patent Publication No. 2002-170239 discloses a third conventional technique for preventing a failure in writing data in a program area of a poor quality disc. A cycle redundancy check (CRC) flag is calculated from ATIP data included in a wobble signal to determine whether the ATIP data is correct. When an error occurs during the calculation of the CRC flag and a sync signal ATIPSYNC of the ATIP data is out of phase with a sync signal SUBSYNC of written data during writing at OPC, a writing speed is reduced and then writing is performed in a test area a second time. Thereafter, data is read from the test area to calculate OPC and writing is performed in the program area using the OPC. In the third conventional technique, since writing is performed in the test area and then in the program area, writing quality can be secured. However, the writing time increases due to writing delays.